A photo-detector array device integrated with a read-out integrated circuit (ROIC) monolithically integrated for a laser-radar image signal and a manufacturing method thereof are provided. According to the photo-detector array device, a photodiode and control devices for selecting and outputting a laser-radar image signal are simultaneously formed on an InP substrate, so that it is possible to simplify manufacturing processes and to greatly increasing yield. In addition, after the photodiode and the control devices are simultaneously formed on the InP substrate, the photodiode and the control devices are electrically speared from each other by using a polyimide. Therefore, a PN junction surface of the photodiode is buried, so that a surface leakage current can be reduced and an electrical reliability can be improved. In addition, a structure of the control devices can be simplified, so that image signal reception characteristics can be improved.